Harvard creates 'cyborg' human tissue

Scientists at Harvard have created a kind of 'cyborg' human tissue through a 3D network of nanowires.

By embedding a 3D network of functional, biocompatible, nanoscale wires into engineered human tissues, the Harvard research team has created a mesh which allows cell growth -- while at the same time monitoring cellular biological activity.

The scientists were led by the Mark Hyman Jr. Professor of Chemistry at Harvard Charles M. Lieber, and also included Harvard Medical School professor Daniel Kohane, MIT's Robert Langer and Zhigang Suo, the Allen E. and Marilyn M. Puckett Professor of Mechanics and Materials at Harvard's School of Engineering and Applied Sciences.

According to Lieber:

"The current methods we have for monitoring or interacting with living systems are limited. We can use electrodes to measure activity in cells or tissue, but that damages them. With this technology, for the first time, we can work at the same scale as the unit of biological system without interrupting it.

Ultimately, this is about merging tissue with electronics in a way that it becomes difficult to determine where the tissue ends and the electronics begin."

The networks were created through a process "similar to that used to etch microchips." Beginning with a 2D substrate, a mesh of organic polymer was placed around nanoscale wires. Electrodes which connect the silicon wires were then put in place, and then the substrate was dissolved. The result was a sponge-like mesh, which could then be seeded with cells.

The team wanted to develop a bioengineered mesh that was able to track chemical or engineered changes in the embedded tissue. By making the nanoscale "scaffolds" seedable with living cells that grow into tissue, the scientists then were able to test the tissue's senses by growing neurons in the framework and then monitoring the molecule's activities "in response to excitatory neurotransmitters."

Through using the nanoscale silicon wires, the team tracked changes in pH level in a blood vessel, and were also able to track feedback loops between cell groups -- including how heart cells behave on different sides of the organ. Changes in biological signals were also tracked when exposed to cardio- or neuro-stimulating drugs.

There are many potential applications of this technology, but Lieber believes that the pharmaceutical industry will become the first stop. Rather than relying on cultured cells, 3D tissues could more precisely monitor how a new drug would affect a human body.

The study was supported by the National Institutes of Health, the McKnight Foundation, and Children's Hospital Boston.